The invention relates to a device for generating a defined position and orientation of at least one platform to which are connected rod elements in a pivotable manner.
It is known to move a platform in so-called octahedral machines with the aid of six telescopic legs. They allow the movement in six independent degrees of freedom. The telescopic legs are supported in ball joints or gimbal-type joints and are driven by threaded spindles, planetary roll spindles or linear direct drives. The drives are for this purpose integrated into the telescopic legs. Between the end points at the platform and the stationary base frame the telescopic legs thus enclose a triangular area. The joints are arranged at the stationary frame such that the connecting lines, that are formed by the delimiting lines of the triangular area, describe a hexagon. All telescopic legs are connected with one of their ends with non-displaceable joints to the stationary base frame and with their other ends with non-displaceable joints to the platform. All telescopic legs are length-adjustable with a drive between the respective joints. The threaded spindles being used have play, are mechanically yielding, and thus allow only for a limited dynamic in a position control circuit, respectively, only a limited positioning precision. Since in each one of the telescopic legs numerous mechanical elements for generating the movement and for transmission of the movement are provided, these elements must also be accelerated by the respective motor of the telescopic leg for generating a movement. This reduces the possible acceleration capability for the platform. A change of the orientation of the platform can only be achieved with additional elements, the position of which is motorically changed and which simultaneously are coupled to the positioning process. Thus, even for a constant orientation of the platform, all telescopic legs must follow the positional change.
It is therefore an object of the present invention to embody the aforementioned device such that the platform can be positioned with high precision and high acceleration in a simple manner into the respective position and/or orientation.